The invention refers to a hydraulically actuatable safety valve with a valve housing accommodating two valve bodies movable in opposite direction towards each other within a bore of the housing, two e.g. electromagnetically actuatable pilot valves, and inlet port for connection to a pump, two working ports and two outlet ports for connection to a tank, with each valve body having a working piston which is acted upon by the pressure fluid via control channels and the pilot valves and having control pistons connected to the working piston and regulating the connections between the pump port , the working ports and the tank ports wherein upon occurrence of a faulty switching, the pump port is connected with the working port and the other working port is connected with one of the tank ports.
Safety valves of the above-mentioned type are for example used to control the brake and the clutch of a mechanical press. For safety reasons, such a valve includes two directional control valves so that the braking action is ensured even upon failure of one valve.